Open Hardware Monitor - Monitors temperature sensors, fan speeds, voltages, load and clock speeds, with optional graph.
Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
Guru3D - Guru of 3D: PC Hardware Reviews and tests
Shutter - Shutter is a feature-rich screenshot program.
Geforce Experience - GeForce Experience is a new application from NVIDIA that optimizes your PC in two key ways.
Snipping Tool - Use Snipping Tool to capture a screen shot, or snip, of any object on your screen, and then annotate, save, or share the image